Thanks for your interest! I'm sure you could cap these pieces, but I don't. My pieces have a really nice shine to them after I spray them lightly with Fuse Master Clear Coat Overglaze. I get it from Fusion Headquarters. I've also brushed on a thin coat too when in a hurry. The instructions on the bottle say to fire to 1350F. or above. So you can fire polish and glaze at the same time.